For me 5D already enough cos my iBook with CS2 only support up to 1DmkIIn, 5D and 30D. It is not wise for me to get a 5DmkII or 40D because I need to change my iBook to MacBook and CS2 to CS3...
My iBook has gone through good and bad times with me and definately with stay till its life ends...
For me it doesn't matter cos i never PS so any cam is not an issue.